Summary:
When the following conditions are met, the main size become smaller by the margins in the main axis.
* The aspect ratio is defined
* The main size is not defined
* The cross size is defined
* The main margin is defined
This is because the main margin size is not included when calculating the main size from the aspect ratio.
Closes https://github.com/facebook/yoga/pull/715
Reviewed By: emilsjolander
Differential Revision: D6998988
Pulled By: priteshrnandgaonkar
fbshipit-source-id: f6f69c47ece17bd7c5e41517b96032bf0c149356